Spinal Rod Bending With Angle and Rotation Control

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Solution Overview

Problem

Current methods for bending spinal rods in orthopedic surgery lack precision and efficiency, particularly in achieving the six degrees of freedom required for accurate attachment to vertebrae, leading to increased surgical time and risk of mechanical failure due to arbitrary bending and metal fatigue.

Innovation Solution

A system that determines the relative spatial location of attachment elements and bony structures, converts this information into a digital format, and uses a computer to calculate and deliver shape parameters for precise bending, including angle, rotation, and position adjustments, enabling accurate shaping of surgical linking devices with six degrees of freedom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual bending methods (French Bender) are used to shape spinal rods, then the rods can be bent to fit anatomical structures, but the bending process becomes arbitrary and time-consuming, increasing surgical time and risk of mechanical failure

Engineering Contradiction:
Improveease of rod bendingVSAvoidsurgical time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system performs preliminary determination of bend parameters (location, angle, rotation) using computer calculation based on patient-specific anatomical data before the actual bending operation during surgery. This eliminates arbitrary bending and reduces surgical time by having the bending plan ready in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces the purely mechanical French Bender system with a computer-based calculation system that determines precise bend parameters. The computer system substitutes for manual judgment and arbitrary mechanical bending, providing scientifically calculated bend locations, angles, and rotations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If manual bending methods are used to shape spinal rods, then the rods can be bent, but the determination of bend location, angle and rotation becomes arbitrary, leading to mistakes and metal fatigue

Engineering Contradiction:
Improveease of rod bendingVSAvoidbending precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention replaces manual mechanical bending judgment with a computer-based calculation system that precisely determines bend parameters. The computer system substitutes for arbitrary manual determination, providing scientifically calculated bend locations, angles, and rotations based on patient-specific anatomical data.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses feedback from measured anatomical data (spine geometry, attachment point locations) to calculate optimal bend parameters. The computer system processes actual patient anatomy measurements and adjusts bend calculations accordingly, eliminating arbitrary bending decisions.

Inventive Principle:
Principle #23Feedback

3Strength

If French Bender is used for spinal rod bending, then leverage-based bending can be achieved, but the process requires great degree of physician skill and takes extremely long time

Engineering Contradiction:
Improvebending capabilityVSAvoidskill requirement
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention replaces the complex skill-based French Bender operation with a computer-based calculation system. The computer system substitutes for physician skill in determining bend parameters, automatically calculating optimal bend locations, angles, and rotations based on anatomical data without requiring extensive physician expertise.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables self-service by allowing the computer to automatically determine bend parameters without requiring great physician skill. The computer-based system performs the complex calculation and decision-making functions that previously required highly skilled physicians, making the process more accessible and efficient.

Inventive Principle:
Principle #25Self-service

4Productivity

If pre-surgical determination of bend points is used, then automatic shaping can be achieved, but the rod may not accurately fit the attachment points as actually installed in the spine

Engineering Contradiction:
Improveshaping efficiencyVSAvoidfit accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system uses feedback from actual surgical attachment point locations to adjust and refine bend calculations. Rather than relying solely on pre-surgical planning, the computer system incorporates real-time anatomical measurements and attachment point data to ensure accurate fit, combining pre-surgical efficiency with intraoperative precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static pre-surgical planning to dynamic intraoperative adjustment. The computer-based system can adapt bend calculations based on actual anatomical variations discovered during surgery, allowing the shaping process to respond to real-time conditions rather than relying on predetermined plans.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3461444B1System for designing and forming a surgical implant
Publication Date: 2022.01.19 NUVASIVE INC
  • EP3461444B1 patent drawingFigure 1
  • EP3461444B1 patent drawingFigure 2~3
  • EP3461444B1 patent drawingFigure 4~5b

AI summary

A device (70) for bending a spinal rod (10) comprises a fixed die (82) and a moving die (71) to receive the rod between them. The fixed and moving dies are supported by first and second elongated handles (71,72) respectively which are pivotally engaged with each other. An angle gauge (85) is positioned between the first and second elongated handles. A clamp (75) is mounted to one of the first and second elongated members configured to engage the spinal rod and a dial (90) is associated with the clamp and configured to rotate the clamp about the longitudinal axis of the rod to a predetermined angular orientation.